The handlebars for motorcycles generally comprise a bent-iron tube so as to define a median section for fixing the handlebar to the fork head, said fixing generally occurring by means of an appropriate bracket, of two end sections for holding the handlebar and of two intermediate linking sections.
As it is known, all the components of the frame of motorcycles for cross-country use must have high resistance as they suffer high intensity shocks and stresses.
It is also known the fact that motorcycles, and in particular racing motorcycles, must generally have light structure for improving their performance and their ease of drive.
However, these two needs are often in opposition since the use of lighter materials or of lightened structures can sometimes jeopardise the resistance of the motorcycle's components.
One of the motorcycle's components that during these last years for the above mentioned grounds has undergone lightening interventions is for instance the handlebar.
Recently, particularly light handlebars having an high capability of absorbing vibrations and made of aluminium alloy have been introduced.
The inventors of the present invention noted that, in particular in handlebars for cross-country motorcycles or in general motorcycles for off-road use, dirt such as earth and mud penetrate in the spaces between the handlebar aluminium structure and the cylindrical control sleeve of the accelerator. That, since control sleeve of the accelerator is usually made of plastic or metal and since aluminium does not help an easy sliding and is quickly damaged by abrasion, makes the sliding of the accelerator sleeve on the handlebar more and more difficult, and in some case can even completely blocks and seizes the sleeve up.
However, in particular in motorbike competitions, it is desired reducing as much as possible the friction between the accelerator sleeve and the support on which the sleeve rotates, so as to achieve the best sensibility of the accelerator twist grip.
An object of the present invention is providing a light alloy handlebar for cycles or motorcycles that allows a better operation of the accelerator twist grip, or of other accelerator control elements, in spite of earth—and mud penetration between the light alloy handlebar structure and the rotatable accelerator control sleeve.